Locks explained
Euro Cylinder Locks: Sizes, Standards and Fitted Cost
A euro cylinder is the keyed barrel on most uPVC and composite doors, also called a lock barrel or cylinder lock. It works the door's lock but is a separate part, so it can be changed on its own. Look for TS 007 3 star or SS 312 Diamond. A change costs £105 to £175 fitted (MLA price list; MyJobQuote).
What is a euro cylinder, and where is it used?
The euro cylinder is a profiled barrel held in the door by one long screw through the lock's faceplate. Turning the key rotates a cam in its middle, and the cam drives the lock: on a uPVC or composite door that is a multipoint mechanism, and on a timber or aluminium door it may be a single euro-profile sashlock. People search for it as a lock barrel, a cylinder lock or a door lock cylinder; all three mean the same part. Because the barrel is separate from the mechanism, it is the part changed after lost keys, a house move or a change of tenant, and it is the part graded for snap resistance.
What is a thumb turn cylinder?
A thumb turn cylinder has a key on the outside and a small turn knob on the inside, so you lock and unlock from indoors without a key. That helps in a fire, because nobody has to hunt for a key to get out, and it stops a key being left in the inside face. The trade-off is that a thumb turn should sit well away from glass or a letterbox. The same grades apply: thumb turn versions of TS 007 3 star and SS 312 Diamond cylinders are made in most sizes. Some insurers ask about thumb turns on glazed doors, so check your policy if a glass panel sits near the lock.
How do you measure a euro cylinder?
Cylinders are sold by the distance from the centre of the fixing screw hole to each end, written as two numbers such as 40/50. With the door open, measure along the edge from the centre of the screw that holds the cylinder to the outer face of the barrel, then do the same for the inner face. The two added together give the overall length. The cylinder should sit close to flush with the handle on the outside; one that sticks out a long way is easier to attack. If the numbers fall between sizes, a locksmith carries offset sizes and can tell you which one fits.
Which standard should a euro cylinder meet?
Look for one of these marks on the cylinder face or its packaging:
- TS 007 3 star: the BSI Kitemark grade for a cylinder that resists snapping on its own. - TS 007 1 star cylinder with a 2 star handle: the same protection, shared between the two parts. - Sold Secure SS 312 Diamond: Sold Secure's top cylinder grade.
An unmarked cylinder may meet none of these. BSI and Sold Secure test products, not the people who fit them, so the mark belongs to the part and should be written on your invoice. Insurers usually ask for one of these grades on uPVC and composite doors, though wording varies.
What does a cylinder change cost, and when do you need a locksmith?
A euro cylinder change costs £105 to £175 fitted (MLA price list; MyJobQuote), and an anti-snap grade £137 to £150 fitted (MLA price list; Checkatrade). Extra keys for a standard cylinder run £4 to £7 each, or £10 to £22 for a high-security or restricted key (MLA key cutting prices; Home Secure Shop). Call a locksmith if the key turns but the door will not lock, if the cylinder is loose or broken, if you have no working key, or if you want several doors keyed alike. A stiff key often points to the mechanism or a dropped door rather than the cylinder itself.
Common questions
Is a lock barrel the same as a euro cylinder?
Usually, yes. In the UK "lock barrel" and "cylinder lock" are everyday names for the euro cylinder. Oval and rim cylinders exist too, so check the shape of yours before buying a replacement.
Can I change a euro cylinder myself?
With a working key and the right size, many people do. If you have no key, the cylinder is damaged, or the door will not lock afterwards, a locksmith is the safer choice.
Do all euro cylinders resist snapping?
No. Only cylinders tested to TS 007 3 star or SS 312 Diamond, or a 1 star cylinder paired with a 2 star handle, are graded for it. Basic cylinders carry no such grade.
Can several doors use the same key?
Yes. Cylinders can be supplied keyed alike, so one key works the front and back doors. A locksmith orders them as a set, and the grade can still be TS 007 3 star or SS 312 Diamond.